Q_RAD
Excel Usage
=Q_RAD(emissivity, T, T_surr)emissivity(float, required): Emissivity of the surface (-)T(float, required): Surface temperature (K)T_surr(float, optional, default: 0): Temperature of surroundings (K). Default 0.
Returns (float): Radiant heat flux (W/m^2)
Examples
Example 1: Blackbody at 400K
Inputs:
| emissivity | T |
|---|---|
| 1 | 400 |
Excel formula:
=Q_RAD(1, 400)Expected output:
"Error: could not convert string to float: \"Error: could not convert string to float: 'Error: string is too long to generate repr'\""
Example 2: Greybody exchange with surroundings
Inputs:
| emissivity | T | T_surr |
|---|---|---|
| 0.85 | 400 | 305 |
Excel formula:
=Q_RAD(0.85, 400, 305)Expected output:
"Error: could not convert string to float: \"Error: could not convert string to float: 'Error: string is too long to generate repr'\""
Example 3: High temperature radiation
Inputs:
| emissivity | T | T_surr |
|---|---|---|
| 0.9 | 2000 | 300 |
Excel formula:
=Q_RAD(0.9, 2000, 300)Expected output:
"Error: could not convert string to float: \"Error: could not convert string to float: 'Error: string is too long to generate repr'\""
Example 4: Low emissivity surface
Inputs:
| emissivity | T | T_surr |
|---|---|---|
| 0.05 | 300 | 290 |
Excel formula:
=Q_RAD(0.05, 300, 290)Expected output:
"Error: could not convert string to float: \"Error: could not convert string to float: 'Error: string is too long to generate repr'\""
Python Code
from ht.radiation import q_rad
def q_rad(emissivity, T, T_surr=0):
"""
Radiant heat flux of a surface.
See: https://ht.readthedocs.io/en/latest/ht.radiation.html#ht.radiation.q_rad
This example function is provided as-is without any representation of accuracy.
Args:
emissivity (float): Emissivity of the surface (-)
T (float): Surface temperature (K)
T_surr (float, optional): Temperature of surroundings (K). Default 0. Default is 0.
Returns:
float: Radiant heat flux (W/m^2)
"""
try:
return float(q_rad(float(emissivity), float(T), float(T_surr)))
except Exception as e:
return f"Error: {str(e)}"